A key component of most computers is an assembly that is referred to as a magnetic disk drive, or hard disk drive. The magnetic disk drive includes a rotating magnetic disk, write and read heads that are suspended by a suspension arm adjacent to a surface of the rotating magnetic disk and an actuator that swings the suspension arm to place the read and write heads over selected circular tracks on the rotating disk. The read and write heads are directly located on a slider that has an air bearing surface (ABS). When the slider rides on the air bearing, the write and read heads are employed for writing magnetic impressions to and reading magnetic impressions from the rotating disk. The read and write heads are connected to processing circuitry that operates according to a computer program to implement the writing and reading functions.
Perpendicular magnetic recording, wherein the recorded bits are stored in a perpendicular or out-of plane orientation in the recording layer, is a promising path toward ultra-high recording densities in magnetic recording hard disk drives. One type of perpendicular magnetic recording system is a system that uses a dual layer media. The dual layer media includes a perpendicular magnetic data recording layer formed on a soft or relatively low coercivity magnetically permeable under-layer. The under-layer serves as a flux return path for the field from the write pole to the return pole of the recording head. The magnetic transitions between adjacent oppositely directed magnetized regions are detectable by the read element or head as the recorded bits.
Magnetic media needs to be made ever smoother for improved reliability and reduced head media spacing. Disk surface roughness can derive from the columnar grains of the perpendicular magnetic recording layer. From the top, the grains resemble the sealed cells of a wasp nest, with the center protruding above the surrounding interfacial layer. The surface of the media can be covered with a protective overcoat that can be formed of carbon. Current methods for smoothing the surface result in defects and corrugations that negatively affect the performance and reliability of the magnetic data recording system. Therefore, there remains a need for a method for manufacturing a magnetic recording medium that can produce a reliably smooth and flat surface on the media.